Abstract:

Exposed printing plates are bent in the area of a bending device to form a
leading end and a trailing end. Each exposed and bent printing plate is
grasped in the area of the bending device at the leading end or at the
trailing end of the printing plate by means of a gripping bar and
transferred together with the gripping bar to a transporting device. The
transporting device transports the printing plate together with the
gripping bar toward a printing press, where the printing plate is removed
together with the gripping bar from the transporting device in the area
of the printing press. While grasped by the gripping bar, the plate is
transferred to a form cylinder of a printing mechanism of the printing
press.

Claims:

1. A method for handling printing plates, the method comprising:placing an
exposed printing plate on a bending table of a bending device;bending the
exposed printing plate in the bending device to form a leading end and a
trailing end;gripping the exposed and bent printing plate in a gripping
bar at one of said leading and trailing ends;transferring the gripping
bar and the printing plate gripped thereby to a transporting
device;transporting the gripping bar and the printing plate gripped
thereby toward the printing press by means of the transporting
device;removing the gripping bar and the printing plate gripped thereby
from the transporting device; andtransferring the printing plate, while
gripped by the gripping bar, from the transporting device to a form
cylinder of a printing mechanism.

2. The method of claim 1 further comprising, after bending the exposed
printing plate on the bending device, swiveling said one of said leading
and trailing ends upward by swiveling said bending table, whereby said
one of said leading and trailing ends can be gripped by said gripping bar
and transferred to said transporting device.

3. The method of claim 1 wherein the transporting device is a trolley, the
method further comprising, after gripping the printing plate, suspending
the printing plate on the trolley by means of the gripping bar.

4. The method of claim 3 wherein the gripping bar and the plated gripped
thereby are removed from the trolley by gripping the gripping bar,
whereupon the printing plate is guided directly to a form cylinder
accessible at floor level.

5. The method of claim 3 wherein the gripping bar and the plated gripped
thereby are removed from the trolley by gripping the gripping bar,
whereupon the printing plate is lifted to a gallery level and guided to a
form cylinder accessible at the gallery level.

6. The method of claim 1 wherein the exposed and bent printing plate is
gripped in correct register by the gripping bar, held in correct register
during transporting, and transferred to the form cylinder in correct
lateral and diagonal register.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The invention is directed to a method for handling printing plates
wherein an exposed printing plate is bent in a bending device to form a
leading end and a trailing end, transported to a printing press, and
clamped to a form cylinder of a printing mechanism.

[0003]2. Description of the Related Art

[0004]Rotary printing presses have printing units with a plurality of
printing mechanisms. For example, printing units in rotary printing
presses conventionally have two or four printing mechanisms, each
printing mechanism comprising a form cylinder on which at least one
printing plate is mounted. The printing plates to be mounted on the form
cylinders of the printing mechanisms of a rotary printing press are
exposed in the area of an exposure device and, after exposure, are bent
in the area of a bending device so as to form a leading end and a
trailing end. After the exposed printing plates are bent in the area of
the bending device, it is necessary to guide the printing plates coming
from the bending device to the printing press, namely, to the printing
mechanisms themselves, so that the printing plates can be mounted on the
form cylinders of the printing mechanisms. Difficulties arise in handling
the printing plates particularly when large-format printing plates with a
large axial width are used because there is a risk that the printing
plates will be damaged during handling between the bending device and the
form cylinders of the printing mechanisms. Therefore, there is a need for
a method for handling printing plates by which even large-format printing
plates can be handled between a bending device and the form cylinders of
the printing mechanisms without the risk of damage.

SUMMARY OF THE INVENTION

[0005]On this basis, an object of the present invention is to provide a
method for handling printing plates by which printing plates can be
handled without the risk of damage.

[0006]According to the invention, every exposed and bent printing plate is
grasped in the area of the bending device at the leading end or at the
trailing end of the printing plate by a gripping bar, also known as a
lock-up bar or clamping bar, and while grasped at the gripping bar is
transferred together with the gripping bar to a transporting device which
transports the respective printing plate together with the gripping bar
in direction of the printing press, and the respective printing plate is
removed together with the gripping bar from the transporting device in
the area of the printing press and while grasped by the gripping bar is
supplied to a form cylinder of a printing mechanism of the printing
press.

[0007]The present invention makes it possible to handle even large-format
printing plates between the bending device and the printing mechanisms of
a printing press without the risk of damage to the printing plates.

[0008]Preferred further developments of the invention are indicated in the
following description. An embodiment example of the invention, which is
not limited thereby, will be described more fully with reference to the
drawings.

[0009]The various features of novelty which characterize the invention are
pointed out with particularity in the claims annexed to and forming a
part of the disclosure. For a better understanding of the invention, its
operating advantages, and specific objects attained by its use, reference
should be had to the drawing and descriptive matter in which there are
illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a schematic view of a printing unit of a rotary printing
press together with a printing plate transporting trolley and a bending
device to illustrate the method, according to the invention, for handling
printing plates;

[0011]FIG. 2 shows a detail from FIG. 1 in the area of the bending device;

[0012]FIGS. 2a, 2b show details of the view according to FIG. 2;

[0013]FIG. 3 shows a detail from FIG. 1 in the area of the printing plate
transporting trolley;

[0014]FIG. 4 shows another detail from FIG. 1 in the area of the printing
unit;

[0015]FIGS. 4a, 4b show details from the view in FIG. 4; and

[0016]FIG. 5 shows an alternative schematic view of a printing unit of a
rotary printing press together with a printing plate transporting trolley
and a bending device to illustrate the method, according to the
invention, for handling printing plates.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0017]FIG. 1 shows a schematic view of a printing unit 10 of a rotary
printing press which, as can be seen from FIG. 4, includes two printing
mechanisms 11, 12 positioned one above the other. A lower printing
mechanism 12 is accessible from a shop floor 13 while an upper printing
mechanism 11 is accessible from a gallery level 14 positioned above the
shop floor 13. The printing unit 10 shown in the drawing is that of an
illustration printing press in which a substrate to be printed is moved
in horizontal direction through the printing unit 10. FIG. 4 shows form
cylinder 15 and transfer cylinder 16 of the printing mechanisms 11, 12 of
the printing unit 10. The transfer cylinders 16 of the printing
mechanisms 11, 12 roll against one another while forming a printing gap
for the substrate to be printed.

[0018]Printing plates are clamped to the form cylinders 15 of the printing
mechanisms 11, 12 of the printing unit 10. The printing plates are bent
in the area of a bending device 17 at a leading end and a trailing end.
The bending device 17 includes a bending machine 18 and a bending table
19, shown in FIG. 5. In the area of the bending machine 18, exposed
printing plates are bent in the area of the leading end and trailing end.
The bending table 19 serves at least for handling the bent printing
plates directly following the bending machine 18, namely, for removing
the bent printing plates from the bending machine 18. If required, the
bending table 19 also serves for handling printing plates which are not
yet bent in order to guide the latter to the bending machine 18 for
bending.

[0019]The printing plates which are bent in the area of the bending device
17 must be guided to the printing mechanisms 11, 12 of the printing unit
10 as they emerge from the bending device 17 so that they can be clamped
to the form cylinders 15 of the printing mechanisms 11, 12. Within the
meaning of the present invention, it is suggested that every printing
plate which is bent in the area of the bending device 17 is grasped at
its leading end or trailing end by a gripping bar 20, also known as a
lock-up bar or clamping bar, and while grasped by the gripping bar 20, is
transferred together with the gripping bar 20 to a transporting device.
By means of the transporting device, the respective printing plate is
transported together with the gripping bar 20 in direction of the
printing mechanism 10 of the printing press. The respective printing
plate is removed from the transporting device together with the gripping
bar 20 in the area of the printing mechanism 10 and, while grasped by the
gripping bar 20, is guided to a form cylinder 15 of a printing mechanism
of the printing unit 10.

[0020]As can be seen most clearly from FIG. 2, every bent printing plate
21, starting from a horizontal position, is swiveled into the transfer
position shown in FIG. 2 in the area of the bending table 19, which is
constructed so as to be swivelable, in such a way that the respective
printing plate 21 can be grasped by the gripping bar 20 at the swiveled
up edge, namely, at the leading edge or at the trailing edge. The
printing plate 21 which is grasped in this way is then transferred to the
transporting device together with the gripping bar 20, namely, in such a
way that direct contact between the respective printing plate 21 and the
transporting device is prevented. The swiveling of the bending table 19
is illustrated in FIG. 2 by a double arrow 22.

[0021]The gripping bar 20 serves to grasp the printing plate 21 correctly
with respect to register in the area of the bending device 17 at the
leading edge or trailing edge of the printing plate 21. The gripping bar
20 includes a device by which the printing plate 21 is fixed in a flat
manner by frictional and positive engagement to a surface region thereof
extending adjacent to the leading edge or trailing edge of the printing
plate 21. This flat, frictionally engaging fixation ensures that the
printing plate 21 is stiffened and, therefore, stabilized in the area of
the gripping bar 20 so that there is no risk that the printing plate 21
will buckle owing to its own weight when handled by the gripping bar 20.
The device of the gripping bar 20 for fixing in a flat, frictionally
engaging manner is formed by two clamping legs 23, 24 (see FIGS. 2a, 2b).
The clamping legs 23, 24 are connected to one another by spring elements
25 and mounted so that they can be swiveled relative to one another
against the spring force of the spring elements 25. When the clamping
legs 23, 24 are swiveled relative to one another against the spring force
provided by the spring elements 25, a clamping area 26 defined by the
clamping legs 23, 24 is opened for inserting a printing plate 21 to be
handled by the gripping bar 20. The clamping area 26 can then be closed
by the spring force of the spring elements 25 so that a printing plate 21
inserted into the clamping area 26 is fixed by frictional engagement.
Handling grips 27 are associated with the gripping bar 20. The operator
can grasp the gripping bar 20 by means of the handling grips 27, that is,
particularly when a printing plate 21 is fixed to the gripping bar 20.
The handling grips 27 are associated with one of the clamping legs 23.

[0022]The gripping bar 20 includes a device for grasping the printing
plate 11 correctly with respect to register. The device for grasping the
printing plate 11 in correct register has guide pins 40 formed at both
sides of the clamping legs 23, 24.

[0023]As is shown in FIGS. 2 and 2a, the guide pins 40 can be inserted
into guide grooves 41 of the bending table 19 in such a way that a
printing plate 21 which is held ready at the bending table 19 is received
in the clamping legs 23, 24 in correct register. According to FIGS. 2,
2a, a printing plate 21 to be received by the gripping bar 20 is aligned
in correct register at stops 42, 43 of the bending table 19. The printing
plate 21 which is aligned in correct register at the bending table 19 is
then received in correct register in the gripping bar 20 by means of the
cooperation of the guide pins 40 of the gripping bar 20 and the guide
grooves 41 of the bending table 19.

[0024]A printing plate 21 received in correct register in the gripping bar
20 remains aligned in correct register in the gripping bar 20 along the
entire transporting path until the printing plate 21 is transferred to a
printing mechanism of a printing press. When the printing plate 21 is
transferred to a printing mechanism of a printing press, the guide pins
40 of the gripping bar 20 can be inserted (see FIG. 4a) into guide
grooves 44 of a printing mechanism in such a way that a printing plate
received in correct register in the clamping legs 23, 24 of the gripping
bar 20 is transferred to the printing mechanism in correct register,
namely, in correct lateral register and in correct diagonal register.

[0025]In the embodiment example shown in FIG. 1, a printing plate 21 fixed
to a gripping bar 20, after removal from the bending table 19, is
suspended in a printing plate transporting trolley 28 without coming into
contact with the printing plate transporting trolley 28 so that the plate
21 cannot be damaged by the latter. The printing plate 21 fixed to the
gripping bar 20 is transported from the bending device 17 in direction of
the printing unit 10 by means of the printing plate transporting trolley
28.

[0027]An angled mounting frame 31 having two portions 32, 33 which are
angled relative to one another is fastened to the trolley platform 30 of
the printing plate transporting trolley 28. A stacking plate 34 which is
mounted at an inclination on the trolley platform 30 to form an oblique
plane is fastened to a lower portion 32 of the mounting frame 31.
Printing plates which are not bent can be positioned to form a stack on
the side 35 of the stacking plate 34 that encloses an angle of greater
than 90° with a horizontal plane of the trolley platform 30.

[0028]The upper portion 33 of the mounting frame 31 is angled in such a
way relative to the lower portion 32 at which the support plate 34 is
mounted that the upper portion 33 of the mounting frame 31 is slants away
from the support plate 34. Holding devices on which bent printing plates
21 are suspended by the gripping bar 20 together with the gripping bar 20
are fastened to the upper portion 33 of the mounting frame 31. Bent
printing plates 21 are accordingly suspended in the area of the side 36
of the stacking plate 34 that encloses an angle of less than 90°
with the horizontal plane of the trolley platform 30. A plurality of bent
printing plates 21 can be suspended at the holding devices so as to
extend parallel to one another.

[0029]As is shown in FIG. 1, printing plates 21 which are suspended at the
printing plate transporting trolley 28 by the gripping bars 20 in the
manner described above are transported in direction of the printing unit
10 of the printing press by means of the printing plate transporting
trolley. A printing plate 21 which is to be clamped to the form cylinder
15 of the printing mechanism 12 which is accessible from the shop floor
13 is then removed from the printing plate transporting trolley 28 by the
gripping bar 20 and can be guided directly to the form cylinder 15 of the
printing mechanism 12 and clamped on the form cylinder 15.

[0030]A printing plate 21 to be clamped on the form cylinder 15 of the
printing mechanism 11 which is accessible from the gallery level 14 is
likewise removed from the printing plate transporting trolley 28 by the
gripping bar 20 and is initially transferred to a lifting device 37 for
lifting the printing plate 21 to the level of the gallery 14. The lifted
printing plate 21 is then moved again in horizontal direction and
accordingly guided to the printing mechanism 11 for subsequently clamping
on the form cylinder 15 of this printing mechanism 11. The movement of
the lifted printing plate 21 in horizontal direction is carried out by
means of a carriage 39 engaging a rail 38.

[0031]When the printing plates 21 are shifted into the area of the
printing mechanisms 11, 12 on whose form cylinders 15 they are to be
clamped, the respective printing plate 21 is guided to the respective
form cylinder 15 in correct register in such a way that the printing
plate 21 is suspended by the guide pins 40 of the gripping bar 20 at the
guide grooves 44 (see FIG. 4) positioned in the area of the respective
printing mechanism. After being released by the gripping bar 20, the
printing plate 21 can be clamped to the form cylinder 15 of the
respective printing mechanism 11, 12 by a printing plate changing device
45 (see FIG. 4).

[0032]FIG. 5 shows a variant of the invention in which the printing plate
transporting trolley 28 can be dispensed with. The rail 38 accordingly
extends into the area of the bending device 17.

[0033]Bent printing plates can be reliably transported between the bending
device 17 and the printing mechanism 10 of the printing press by means of
the present invention without the risk of damaging the bent printing
plates 21. In so doing, direct contact between the printing plates 21 and
printing plate transporting device, particularly direct contact with the
printing plate transporting trolley 28, is prevented. The printing plates
21 are fixed to a gripping bar 20 in the area of a leading end or a
trailing end of the printing plates over the entire course of
transporting between the bending device 17 and the printing unit 10.

[0034]The printing plates 21 remain connected to the gripping bar 20 and
aligned in correct register in the gripping bar 20 over the entire
transporting path. Printing plates 21 which are clamped to the gripping
bar 20 can be lifted into the area of upper printing mechanisms by means
of a lifting device 37. The swivelable bending table 19, by means of
which a bent printing plate can be swiveled into a transfer position in
the area of the bending device 17, facilitates the grasping of a bent
printing plate by a gripping bar 20 in the area of a leading end or
trailing end thereof.

[0035]In the same way that new printing plates are transported from the
bending device 17 in direction of the printing unit 10, used printing
plates can also be returned in the opposite manner.

[0036]Devices for storing and transmitting information for automatic
transporting of printing plates 21 held at the gripping bars 20 can be
associated with the gripping bars 20. These devices for storing and
transmitting information can be, e.g., RFID tags.

[0037]The invention is not limited by the embodiments described above
which are presented as examples only but can be modified in various ways
within the scope of protection defined by the appended patent claims.